Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with a part in your car that helps control the temperature of a special fluid used to clean the exhaust. It's like a thermostat for this fluid, and it's not working right.
The P20B1 code is triggered when the Engine Control Module (ECM) detects an issue with the circuit or wiring connected to the reductant heater coolant control valve.
The reductant heater coolant control valve is responsible for regulating the flow of coolant to the reductant heater. This valve ensures that the reductant (typically Diesel Exhaust Fluid, or DEF) is kept at an optimal temperature for effective exhaust treatment. An open circuit or fault in the control valve can lead to improper temperature regulation, affecting emissions control.
• Check Engine Light illuminated
• Poor fuel efficiency
• Increased exhaust emissions
• Faulty reductant heater coolant control valve
• Damaged wiring or connectors in the valve circuit
• Faulty Engine Control Module (ECM)
Reductant: A substance used in diesel engines to reduce emissions, typically Diesel Exhaust Fluid (DEF).
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the P20B1 code.
• Inspect the wiring and connectors for damage or corrosion.
• Test the reductant heater coolant control valve for proper operation.
• Replace the reductant heater coolant control valve if faulty.
• Repair or replace damaged wiring or connectors.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado
• Ram 2500
• Regular maintenance checks
• Ensure proper DEF levels
• Inspect wiring for wear and tear
Sensor Issue
• Have your vehicle inspected by a professional if the Check Engine Light is on.
• Avoid ignoring the issue, as it can lead to more serious problems.
Check with your vehicle manufacturer for warranty coverage on emissions-related components.
This code has become more common with the increased use of DEF systems in diesel vehicles to meet emissions standards.
Moderate – Address the issue to ensure proper emissions control and avoid potential fines.
Driving with a malfunctioning emissions system may violate emissions regulations and can lead to fines.
• Engine at operating temperature
• Vehicle in park or neutral
The reductant heater coolant control valve is typically located near the DEF tank or along the coolant lines leading to the DEF system.
Q: Can I drive with a P20B1 code?
A: While you can drive with this code, it is not recommended as it may lead to increased emissions and potential legal issues.
Q: How can I prevent a P20B1 code?
A: Regular maintenance and inspections can help prevent issues with the reductant heater coolant control valve.
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